EXPRESSION OF A TRANSACTIVATION-DEFICIENT FORM OF THYROID TRANSCRIPTION FACTOR-I DECREASES THE ACTIVITY OF CO-TRANSFECTED THYROGLOBULIN ANDTHYROPEROXIDASE PROMOTERS
C. Christophehobertus et al., EXPRESSION OF A TRANSACTIVATION-DEFICIENT FORM OF THYROID TRANSCRIPTION FACTOR-I DECREASES THE ACTIVITY OF CO-TRANSFECTED THYROGLOBULIN ANDTHYROPEROXIDASE PROMOTERS, FEBS letters, 399(1-2), 1996, pp. 140-142
Thyroid transcription factor I(TTF-1) plays a critical role in thyroid
organogenesis and in the control of expression of several thyroid-spe
cific genes, like those coding for thyroglobulin and thyroperoxidase.
We have expressed the isolated DNA-binding homeodomain of TTF-I in cul
tured thyroid cells by transient transfection. A specific reduction in
the activity of cotransfected thyroglobulin and thyroperoxidase promo
ters was observed in the presence of the isolated TTF-1 homeodomain, a
s compared to their activity measured in the presence of a mutated hom
eodomain unable to bind DNA. The activity of the SV40 early promoter,
used as a control, was only marginally affected in these experiments.
The transactivation-deficient form of TTF-1 described here may thus be
used for investigating other cellular processes that are dependent on
TTF-1 transcriptional activity.